Microwave ablation catheter and method of utilizing the same

ABSTRACT

A method for treating tissue through a branched luminal network of a patient is provided. A pathway to a point of interest in branched luminal network of a patient is generated. An extended working channel is advanced transorally into the branched luminal network and along the pathway to the point of interest. The extended working channel may be positioned in a substantially fixed orientation at the point interest. A tool is advanced though the extended working channel to the point of interest. Tissue at the point of interest is treated.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of and priority to U.S.Provisional Patent Application Ser. No. 61/680,555 filed on Aug. 7, 2012by Brannan et al.; U.S. Provisional Patent Application Ser. No.61/783,921 filed on Mar. 14, 2013 by Ladtkow et al.; U.S. ProvisionalPatent Application Ser. No. 61/784,048 filed on Mar. 14, 2013 by Ladtkowet al.; U.S. Provisional Patent Application Ser. No. 61/784,176 filed onMar. 14, 2013 by Ladtkow et al.; U.S. Provisional Patent ApplicationSer. No. 61/784,297 filed on Mar. 14, 2013 by Ladtkow et al.; and U.S.Provisional Patent Application Ser. No. 61/784,407 filed on Mar. 14,2013 by Ladtkow et al., the entire contents of each being incorporatedherein by reference.

BACKGROUND Technical Field

The present disclosure relates to a microwave ablation catheter andmethod of utilizing the same. More particularly, the present disclosurerelates to a microwave ablation catheter that is positionable throughone or more branched luminal networks of a patient for treating tissue.

Description of Related Art

Microwave ablation may be utilized for treating various maladies, e.g.,nodules, of different organs like the liver, brain, heart, lung andkidney. When a nodule is found, for example, within a lung, severalfactors are considered in making a diagnosis. For example, a biopsy ofthe nodule may be taken using a biopsy tool under CT guidance. If thebiopsy reveals that the nodule is malignant, it may prove useful toablate the nodule. In this instance, microwave ablation, which typicallyincludes transmitting microwave energy to a percutaneous needle, may beutilized to ablate the nodule. Under certain surgical scenarios, certaincurrent percutaneous methods of microwave ablation procedures can resultin pneumothoraces (air leaks) and a collection of air in the spacearound the lungs which if not appreciated by the clinician canultimately lead to collapse of the lung or a portion thereof.

Endobronchial navigation uses CT image data to create a navigation planto facilitate advancing a navigation catheter (or other suitable device)through a bronchoscope and a branch of the bronchus of a patient to thenodule. Electromagnetic tracking may also may be utilized in conjunctionwith the CT data to facilitate guiding the navigation catheter throughthe branch of the bronchus to the nodule. In certain instances, thenavigation catheter may be positioned within one of the airways of thebranched luminal networks adjacent to or within the nodule or point ofinterest to provide access for one or more tools. Once the navigationcatheter is in position, fluoroscopy may be used to visualize biopsytools, such as, for example, biopsy brushes, needle brushes and biopsyforceps as they are passed through the navigation catheter and into thelung and to the nodule or point of interest.

SUMMARY

As can be appreciated, a microwave ablation catheter that ispositionable through one or more branched luminal networks of a patientto treat tissue may prove useful in the surgical arena.

Aspects of the present disclosure are described in detail with referenceto the drawing figures wherein like reference numerals identify similaror identical elements. As used herein, the term “distal” refers to theportion that is being described which is further from a user, while theterm “proximal” refers to the portion that is being described which iscloser to a user.

An aspect of the present disclosure provides a method for treatingtissue through a branched luminal network of a patient. A pathway to apoint of interest in branched luminal network of a patient is generated.An extended working channel is advanced transorally into the branchedluminal network and along the pathway to the point of interest. Theextended working channel may be positioned in a substantially fixedorientation at the point interest. A tool is advanced though theextended working channel to the point of interest. Tissue at the pointof interest is treated.

A scope may be positioned within a patient. A locatable guide may bepositioned within the extended working channel for positioning theextended working channel to the point of interest. Prior to advancingthe tool through the extended working channel, the locatable guide maybe removed from the extended working channel.

The tool may be a microwave ablation catheter, a biopsy brush, needlebrushes and biopsy forceps. The tissue may be biopsied. The tissue maybe ablated. Prior to treating the tissue, placement of the extendedworking channel at the point of interest may be confirmed. The tissuemay be penetrated at the point of interest. Effective treatment of thetissue may be confirmed.

The microwave ablation catheter may be provided with a coaxial cablethat is connected at its proximal end to a microwave energy source andat its distal end to a distal radiating section. The coaxial cableincludes inner and outer conductors and a dielectric positionedtherebetween. The inner conductor extends distally past the outerconductor and is in sealed engagement with the distal radiating section.A balun is formed in part from a conductive material electricallyconnected to the outer conductor of the coaxial cable and extends alongat least a portion of the coaxial cable. The conductive material has abraided configuration and is covered by at least one insulativematerial.

Generating a pathway to a point of interest may include utilizing aguidance system that is configured for planning the pathway to the pointof interest and for guiding and navigating one of the tool, extendedworking channel or the locatable guide through the branched luminalnetwork of a patient. The pathway may be generated based on computedtomographic (CT) data of the luminal network, and may be displayed in agenerated model. The pathway may be generated from CT data to identify apathway to the point of interest identified by a user in the CT data,and the pathway may be generated for acceptance by the user before usein navigating.

A plurality of sensors may be positioned adjacent the tissue. Theplurality of sensors may be configured to communicate with at least onecontroller that is in communication with one of the guidance system andthe microwave energy source. One or more of the plurality of sensors maybe pointed within an airway adjacent the tissue.

The plurality of sensors may be utilized to measure at least oneproperty of the tissue. The property of the tissue may be impedance ofthe tissue, temperature of the tissue or dielectric of the tissue.

BRIEF DESCRIPTION OF THE DRAWING

Various embodiments of the present disclosure are described hereinbelowwith references to the drawings, wherein:

FIG. 1 is a perspective view of a microwave ablation system including amicrowave ablation catheter assembly configured for use with a microwaveablation system according to an embodiment of the instant disclosure;

FIG. 2 is a front view of an embodiment of a lumen configurationconfigured for use with the microwave catheter assembly shown in FIG. 1;

FIG. 3A is a front view of an another embodiment of a lumenconfiguration configured for use with the microwave catheter assemblyshown in FIG. 1;

FIG. 3B is a front view of an another embodiment of a lumenconfiguration configured for use with the microwave catheter assemblyshown in FIG. 1;

FIG. 3C is a front view of an another embodiment of a lumenconfiguration configured for use with the microwave catheter assemblyshown in FIG. 1, whereby the lumen supporting the coaxial microwavestructure also communicates cooling fluid with inflow or outflow ports;

FIG. 4 is a perspective view of a distal end of a microwave ablationcatheter configured for use with the microwave ablation assembly shownin FIG. 1;

FIG. 5 is a cross-sectional view taken along line section 5-5 in FIG. 4;

FIG. 6 is a screen shot of a CT based luminal navigation system inaccordance with an embodiment of the present disclosure;

FIG. 7 is a perspective view of a microwave ablation system and luminalnavigation system configured for use the microwave ablation catheterassembly shown in FIG. 1 and microwave ablation catheter shown in FIG. 2in accordance with an embodiment of the present disclosure;

FIG. 8 is a side view of a luminal catheter delivery assembly includingan extended working channel and locatable guide catheter in accordancewith an embodiment of the present disclosure;

FIG. 9 is a partial, perspective view of a distal end of the locatableguide catheter shown in FIG. 8;

FIG. 10 is a side view of the extended working channel shown in FIG. 8with the microwave ablation catheter extending from a distal endthereof;

FIG. 11 is a screen shot of a CT based luminal navigation system inaccordance with an embodiment of the present disclosure;

FIG. 12A is a schematic, plan view of the extended working channelpositioned within a bronchoscope prior to being positioned within atrachea of a patient;

FIG. 12B is a schematic, plan view of the bronchoscope shown in FIG. 12Apositioned within the trachea of the patient with the extended workingchannel extending distally therefrom;

FIG. 12C is a partial, cutaway view of the extended working channel andlocatable guide positioned within the bronchoscope;

FIG. 13A is a schematic, plan view of the bronchoscope positioned withinthe trachea of the patient with the extended working channel extendingdistally therefrom;

FIG. 13B is a partial, cutaway view of the extended working channel anda biopsy tool positioned within the bronchoscope;

FIG. 14 is a schematic, plan view of the bronchoscope positioned withinthe trachea of the patient with the extended working channel removedfrom the bronchoscope;

FIG. 15A is a schematic, plan view of the bronchoscope positioned withinthe trachea of the patient with an extended working channel according toan alternate embodiment extending distally therefrom;

FIG. 15B is a partial, cutaway view of the extended working channelshown in FIG. 15A positioned within the bronchoscope;

FIG. 16A is a schematic, plan view of the bronchoscope positioned withinthe trachea of the patient with the extended working channel shown inFIG. 15A extending distally therefrom;

FIG. 16B is a schematic, plan view of the bronchoscope positioned withinthe trachea of the patient with the extended working channel shown inFIG. 15A extending distally therefrom and adjacent target tissue;

FIG. 16C is a partial, cutaway view of the extended working channel andthe microwave ablation catheter shown in FIG. 2 coupled to one anotherand positioned within the bronchoscope;

FIG. 16D is a cross-sectional view taken along line section 16D-16D inFIG. 16C;

FIG. 17 is a schematic, plan view of another embodiment of the extendedworking shown in FIGS. 9 and 15A with the extended working channelpositioned within the lung of a patient and having a balloon coupledthereto in an deflated configuration;

FIG. 18 is an enlarged area of detail of FIG. 17 and showing the balloonin an inflated configuration;

FIG. 19A is a schematic, plan view of an alternate embodiment of a balunconfigured for use with the microwave ablation catheter shown in FIG. 2with the balun shown in an expanded configuration;

FIG. 19B is a schematic, plan view of the balun shown in FIG. 19A in annon-expanded configuration;

FIG. 20 is a schematic, plan view of a distal tip configuration that maybe utilized with the microwave ablation catheter assembly shown in FIG.1, the microwave ablation catheter shown in FIG. 2 or the extendedworking channel shown in FIG. 15A;

FIG. 21 is a schematic, plan view of an alternate embodiment of theextended working channel shown in FIG. 15A;

FIG. 22 is a schematic, plan view of yet another embodiment of theextended working channel shown in FIG. 15A;

FIG. 23 is a perspective view of an alternate embodiment of the luminalnavigation system shown in FIG. 7;

FIG. 24 is a partial, cutaway view of another embodiment of themicrowave ablation catheter shown in FIG. 1;

FIG. 25 is a cross-sectional view taken along line section 25-25 in FIG.24;

FIG. 26 is a cross-sectional view taken along line section 26-26 in FIG.24;

FIG. 27 is a partial, cutaway view of yet another embodiment of themicrowave ablation catheter shown in FIG. 1;

FIG. 28 is a schematic, plan view of still yet another embodiment of themicrowave ablation catheter shown in FIG. 1;

FIG. 29 is a schematic, plan view illustrating a circulation feedbackloop that is configured for use with the extended working channels shownin FIGS. 15A, 17 and 21, and the microwave ablation catheter shown inFIGS. 1, 24 and 27-28;

FIG. 30 is a schematic, plan view of still yet another embodiment of theextended working channel shown in FIG. 15A;

FIG. 31 is a schematic, plan view of still yet another embodiment of theextended working channel shown in FIG. 15A with the microwave ablationcatheter shown in FIG. 2 in a retracted configuration;

FIG. 32 is a schematic, plan view of the extended working channel shownin FIG. 31 with the microwave ablation catheter shown in an extendedconfiguration;

FIG. 33 is a schematic, plan view of still yet another embodiment of theextended working channel shown in FIG. 15A;

FIG. 34 is a schematic, plan view of still yet another embodiment of theextended working channel shown in FIG. 15A with the extended workingchannel shown in a non-expanded configuration;

FIG. 35 is a schematic, plan view of the extended working channel shownin FIG. 34 in an expanded configuration;

FIG. 36A is a front view of an alternate embodiment of the microwaveablation catheter shown in FIG. 2 including a conductive balloon coupledthereto and shown in a deflated configuration;

FIG. 36B is a front view of the microwave catheter shown in FIG. 36Awith the conductive balloon shown in an inflated configuration;

FIG. 37A is a front view of an alternate embodiment of the microwaveablation catheter shown in FIG. 2 including a plurality of thermallyconductive fins coupled thereto and shown in a non-deployedconfiguration;

FIG. 37B is a front view of the microwave catheter shown in FIG. 37Awith the plurality of thermally conductive fins shown in a deployedconfiguration;

FIG. 38 is a schematic, plan view of still yet another embodiment of theextended working channel shown in FIG. 15A;

FIG. 39A is a schematic, plan view of an alternate embodiment of themicrowave ablation catheter shown in FIG. 2 including a balloon coupledthereto and shown in a deflated configuration;

FIG. 39B is a schematic, plan view of the microwave catheter shown inFIG. 39A with the balloon shown in an inflated configuration;

FIG. 40A is a schematic, plan view of various fiducial markersconfigured for use with the microwave ablation system shown in FIG. 7,wherein the fiducial markers are shown adjacent target tissue that hasnot been ablated;

FIG. 40B is a schematic, plan view of the fiducial markers shown in FIG.40A, wherein the fiducial markers are shown adjacent target tissue thathas been ablated;

FIG. 41 is a schematic, plan view of a guide wire including a pluralityof thermocouples configured for use with the microwave ablation systemshown in FIG. 7;

FIG. 42 is a perspective view of an electrical measurement systemconfigured for use with the microwave ablation system shown in FIG. 7;

FIG. 43 is a schematic, plan view of a feedback configuration configuredfor use with the microwave ablation system shown in FIG. 7;

FIG. 44 is a schematic, plan view of an another embodiment of a feedbackconfiguration configured for use with the microwave ablation systemshown in FIG. 7;

FIG. 45 is schematic, plan view of a yet another embodiment of afeedback configuration configured for use with the microwave ablationsystem shown in FIG. 7;

FIG. 46A is a fluoroscopic images of a patient, having a catheter placedtherein; and

FIG. 46B is a virtual fluoroscopic image of a patient depicting atarget.

DETAILED DESCRIPTION

Detailed embodiments of the present disclosure are disclosed herein;however, the disclosed embodiments are merely examples of thedisclosure, which may be embodied in various forms. Therefore, specificstructural and functional details disclosed herein are not to beinterpreted as limiting, but merely as a basis for the claims and as arepresentative basis for teaching one skilled in the art to variouslyemploy the present disclosure in virtually any appropriately detailedstructure.

As can be appreciated an energy device, such as a microwave ablationcatheter, that is positionable through one or more branched luminalnetworks of a patient to treat tissue may prove useful in the surgicalarena and the present disclosure is directed to such apparatus, systemsand methods. Access to lumeninal networks may be percutaneous or throughnatural orifice. In the case of natural orifice, an endobronchialapproach may be particularly useful in the treatment of lung disease.Targets, navigation, access and treatment may be plannedpre-procedurally using a combination of imaging and/or planningsoftware. In accordance with these aspects of the present disclosure theplanning software may offer custom guidance using pre-procedure images).Navigation of the luminal network may be accomplished usingimage-guidance. These image-guidance systems may be separate orintegrated with the energy device or a separate access tool and mayinclude MRI, CT, fluoroscopy, ultrasound, electrical impedancetomography, optical, and device tracking systems. Methodologies forlocating the separate or integrated to the energy device or a separateaccess tool include EM, IR, echolocation, optical, and others. Trackingsystems may integrated to imaging device, where tracking is done invirtual space or fused with preoperative or live images. In some casesthe treatment target may be directly accessed from within the lumen,such as for the treatment of the endobronchial wall for COPD, Asthma,lung cancer, etc. In other cases, the energy device and/or an additionalaccess tool may be required to pierce the lumen and extend into othertissues to reach the target, such as for the treatment of disease withinthe parenchyma. Final localization and confirmation of energy deviceplacement may be performed with imaging and/or navigational guidanceusing the modalities listed above. The energy device has the ability todeliver an energy field for treatment (including but not limited toelectromagnetic fields) and may have the ability to monitor treatmentduring energy application. The monitoring of the treatment may includethermometry, electrical impedance, radiometry, density measurement,optical absorption, hydration, ultrasound, and others. Additionally oralternatively treatment may be monitored from within the lumen orextracorporeally using an additional device or the image-guidancemodalities described above. After treatment, the energy device and/or anadditional device may have the ability to confirm adequate treatment wasperformed, employing at least the techniques described above withrespect to treatment monitoring. Further, treatment confirmation may befrom within the lumen or extracorporeal. The long term treatmentperformance may be performed with imaging which may be integrated into afollow-up software application.

One embodiment of the present disclosure is directed, in part, to amicrowave ablation catheter that is positionable through one or morebranched luminal networks of a patient to treat tissue. The microwaveablation catheter is part of an ablation system that includes amicrowave energy source and a planning and navigation system for theplacement of the catheter at a desired location within the luminalnetwork. Further, the system includes imaging modalities that can beemployed to confirm placement of the catheter and the effect of theapplication of energy. The microwave catheter itself may include thecapability to aide in the confirmation of the placement within thetissue to be treated, or additional devices may be used in combinationwith the microwave catheter to confirm placement within the tissue to betreated. Still further, one or more thermocouples or temperature sensorson the microwave catheter detect the temperature of the microwavecatheter or the tissue surrounding the catheter and enable monitoring ofthe microwave catheter temperature and the tissue temperature during andafter treatment both for safety purposes and for dosage and treatmentpattern monitoring purposes. The microwave catheter may also assist inthe access to the target tissue, either intraluminal or outside thelumen. The microwave catheter may also assist in the monitoring of thetreatment through various measurement techniques and may also be usedfor treatment confirmation, in addition to assistance from othermonitoring and confirmation devices.

FIGS. 1-5 depict various aspects of a microwave ablation system 10(system 10). The system 10, as show in FIG. 1 includes a microwaveablation catheter assembly 12 (assembly 12) configured to house amicrowave ablation catheter 14 (ablation catheter 14) (shown in FIG. 4).Assembly 12 and ablation catheter 14 are configured to couple to amicrowave energy source (energy source 16) that is configured totransmit microwave energy to the catheter 14 to treat target tissue,e.g., lung tissue.

The assembly 12 shown in FIG. 1 is configured to receive the ablationcatheter 14 and to provide a pathway for a cooling medium to circulatewithin the assembly 12 and cool the ablation catheter 14 when theablation catheter 14 is energized. With these purposes in mind, assembly12 is formed by overmolding plastic to form a generally elongatedhousing 23 having an outer sheath 18 (FIG. 2) and a plurality of lumens19 a, 19 b, and 19 c extending from a proximal end 20 to a distal end 22that includes a relatively pointed or appropriately rounded distal tip21. A hub portion 24 is provided at the proximal end 20 and includesports 26 a, 26 b, 26 c that couple to corresponding distal ends (notexplicitly shown) of connection tubes 28 a, 28 b, 28 c. Connection tubes28 a, 28 c include respective proximal ends 30 a, 30 c that areconfigured to releasably couple either directly or indirectly to a fluidsource 32 including hoses 31 a, 31 b that provide one or more suitablecooling mediums (e.g., water, saline, air or combination thereof) to theablation catheter 14. In embodiments, the fluid source 32 may be acomponent of a cooling system that is disclosed in U.S. patentapplication Ser. No. ______ having attorney docket no. H-IL-00083, theentirety of which is incorporated herein by reference. A proximal end 30b of connection tube 28 b is configured to couple either directly orindirectly to the energy source 16 to energize the ablation catheter 14.An optional pair of wings 34 a, 34 b may be provided at the proximal end20 of the assembly 12. The wings 34 a, 34 b may extend laterally fromrespective right and left sides of the proximal end 20 and may beconfigured to rest on a patient or to be grasped by a clinician formanipulation of the assembly 12.

The ports 26 a, 26 c of the assembly 12 are in fluid communication withcorresponding lumens 19 a, 19 c of the plurality of lumens 18 providedwithin the assembly 12 (FIG. 2) and are configured to provide one of theaforementioned cooling mediums to the assembly 12. In an embodiment,such as the embodiment illustrated in FIG. 2, port 26 a is an outflowport and provides a point of egress for the cooling medium from outflowlumen 19 a and port 26 c is an inflow port and provides point of ingressfor the cooling medium into the inflow lumen 19 c.

FIG. 3A illustrates an alternate lumen configuration that may beutilized with the assembly 12. In this embodiment, two outflow lumens 19a′ and one inflow lumen 19 c′ are provided and are in fluidcommunication with the respective ports 26 a, 26 c.

FIG. 3B illustrates an alternate lumen configuration that may beutilized with the assembly 12. In this embodiment, two outflow lumens 19a′ and one inflow lumen 19 c′ are provided and are in fluidcommunication with the respective ports 26 a, 26 c. Additionally, thelumen supporting the coaxial microwave structure is also used for eitherfluid inflow or outflow.

FIG. 3C illustrates an alternate lumen configuration similar to FIGS. 3aand 3b that may be utilized with the assembly 12. In this embodiment,two outflow lumens 19 a′ and two inflow lumens 19 c′ are provided andare in fluid communication with the respective ports 26 a, 26 c.

A third lumen 19 b is provided within the assembly 12 and is configuredto support the ablation catheter 14 when the ablation catheter 14 iscoupled to the assembly 12. In the embodiment illustrated in FIG. 2, theoutflow and inflow lumens 19 a, 19 c are formed above the lumen 19 b. Inthe embodiment illustrated in FIG. 3A, the lumen 19 b is centeredbetween the outflow lumens 19 a and inflow lumens 19 c to provide twoopposing outflow lumens 19 a and two opposing inflow lumens 19 c aroundthe lumen 19 b. In the embodiments illustrated in FIGS. 3A and 3B, thelumen 19 b is centered between the outflow lumens 19 a and inflow lumen19 c to provide two opposing outflow lumens 19 a and one opposing inflowlumen 19 c around the lumen 19 b. The lumen configurations illustratedin FIGS. 2 and 3A-3C provide the assembly 12 with the needed flexibilityto move within the relatively thin conductive airways (and/or vessels)in the branch of the bronchus.

In an embodiment, the assembly 12 may include a 4 lumen configuration(not shown). In this embodiment, three (3) outer lumens (e.g., acombination of outflow and inflow lumens 19 a, 19 c, respectively) maybe equally spaced around a center lumen (e.g., lumen 19 b) that isconfigured to support the ablation catheter 14 when the ablationcatheter 14 is coupled to the assembly 12. In one particular embodiment,the three (3) outer lumens may be configured to include two (2) inflowlumens 19 c and one (1) outflow lumen 19 a (or vice versa).

The outflow and inflow lumens 19 a, 19 c extend a predetermined distancewithin the assembly 12 and can function with various coolant feedbackprotocols (e.g., open or closed feedback protocols). In the embodimentsillustrated in FIGS. 2 and 3A-3C, the inflow lumens 19 c extend distallyof the outflow lumens 19 a to allow an adequate amount of cooling mediumto circulate around the ablation catheter 14. It should be understood,regardless of the number of or configuration of lumens, space not filledwithin the lumen supporting the coaxial cable and radiating section maybe used for additional fluid ingress or egress to improve fluid flow anddirectly cool through intimate fluid contact the coaxial microwavestructures. In addition to supporting the ablation catheter, the lumen19 b may also support additional outflow or inflow of coolant, wherebylumen 19 b may couple to connection tubes 28 a, 28 c and theirrespective proximal ends 30 a, 30 c.

Referring now to FIGS. 4 and 5, the ablation catheter 14 is illustrated.Ablation catheter 14 includes a coaxial cable 36. Coaxial cable 36includes a proximal end 38 that couples to port 26 b (shown in FIG. 1)that provides electrical connection to the inner conductor 40 and outerconductor 48 of the coaxial cable 36 and the energy source 16.

A distal radiating section 42 is provided at a distal end 44 of thecoaxial cable 36 and is configured to receive the inner conductor 40, asbest seen in FIG. 5. The distal radiating section 42 may be formed fromany suitable material. In embodiments, the distal radiating section 42may formed from ceramic or metal, e.g., copper, gold, silver, etc. Thedistal radiating section 42 may include any suitable configurationincluding but not limited to a blunt configuration, flat configuration,hemispherical configuration, pointed configuration, bar-bellconfiguration, tissue piercing configuration, etc. The distal radiatingsection 42 may couple to the distal end 44 of the coaxial cable viasoldering, ultrasonic welding, adhesive, or the like. In one embodimentthe distal radiating section 42 is sealed to the inner conductor 40 anda dielectric 50 to prevent fluid from contacting the inner conductor 40.As an alternative, the seal may be just between the inner conductor 40and the dielectric 50.

An outer conductor 48 is braided and extends along the dielectric 50positioned between the inner and outer conductors 40, 48, respectively(FIG. 5). As defined herein braided means made by intertwining three ormore strands, and while described as a braid, the actual construction isnot so limited and may include other formations of outer conductors ofcoaxial cables as would be understood by those of ordinary skill in theart. One advantage of a braided configuration of the outer conductor 48is that it provides the ablation catheter 14 with the flexibility tomove within the relatively narrow luminal structures such as the airwaysof the lungs of a patient. Additionally, through the use of flat wirebraiding and follow on braid compression with an appropriately sizeddie, the cross sectional dimension of the braided conductor may beminimized significantly in comparison to other conductive structures,such as a drawn copper tubing, while maintain an acceptable electricalperformance.

A choke or balun 52 is formed in part of a conductive layer 51 thatextends along a portion of the coaxial cable 36. The conductive layer 51may be a braided material of similar construction as the outer conductor48 and is connected to the outer conductor 48. Specifically, a portionof the outer conductor 48 is shorted (e.g., soldered, interbraided orotherwise affixed) to a proximal portion 54 of the conductive layer 51.

The balun 52 also includes an insulative layer 56, which may be formedof a polytetrafluoroethylene (PTFE). The insulative layer 56 isgenerally formed between the conductive material 52 and the outerconductor 48. The insulative layer 56 extends distally past a distal endof the conductive material 52. The insulative layer 56 and itsorientation extending beyond the conductive layer can be adjusted duringmanufacture to control the overall phase, energy field profile, andtemperature response of the coaxial cable 36.

The outer conductor 48 extends distally beyond the insulative layer 56.A portion of the outer conductor 48 is removed to expose the dielectric50 of the coaxial cable 36 and form a feedgap 58. The feedgap 58 islocated distally from the balun 52 and proximal of and immediatelyadjacent the distal radiating section 42. The feedgap 58 and distalradiating section 42 are located and dimensioned to achieve a specificradiation pattern for the ablation catheter 14.

The ablation catheter 14 may optionally include an outer sheath 62 thatextends to the proximal end 54 of the balun 52. Alternatively, no outersheath 62 is employed and just a thin layer of insulative material 60(e.g., a layer of polyethylene terephthalate (PET)) may be used to covera portion of the outer conductor 48, and the balun 52 up to the pointthe insulative layer 56 extends beyond the conductive layer 51 of thebalun 52 (FIG. 5). In yet a further embodiment the layer of PET 60 maybe configured to extend proximally along the length of the coaxial cable36 to assist in maintaining the braided configuration of the outerconductor 48 and conductive layer 51. As will be appreciated by those ofskill in the art, removal of the outer sheath 62 and replacing it with athin material, either along the length of the coaxial cable 36 or justat the balun 52 increases the flexibility of the ablation catheter 14.This added flexibility is beneficial for enabling greater ranges ofmovement when the ablation catheter 14 is used in luminal networkshaving small diameters and having a branched structure of multiple sharpturns, as will be described in greater detail below.

The flexibility of the ablation catheter 14 can be altered toaccommodate a specific surgical procedure, a specific luminal structure,specific target tissue, a clinician's preference, etc. For example, inan embodiment, it may prove advantageous to have an ablation catheter 14that is very flexible for movement through the relatively narrow airwayof the lungs of a patient. Alternatively, it may prove advantageous tohave an ablation catheter 14 that is only slightly flexible, e.g., wherethe ablation catheter 14 is needed to pierce or puncture target tissue.Still further, to achieve the desired amount of flexibility it may bedesirable to form the balun 52 in a manner consistent with thedisclosure of U.S. patent application Ser. No. ______ (Attorney DocketNo. H-IL-00077 (1988-77) entitled “Microwave Energy-Delivery Device andSystem” the entire contents of which is incorporated herein byreference. Still further, although the microwave ablation catheterdescribed here may be specific, it should be understood to those ofskill in the art that other microwave ablation catheter embodiments,either simplified or more complex in structural detail, may be employedwithout departing from the scope of the instant disclosure.

In embodiments, a temperature monitoring system 3 (FIG. 1), e.g.,microwave thermometry, may be utilized with the ablation catheter 14 toobserve/monitor tissue temperatures in or adjacent an ablation zone. Inan embodiment, for example, one or more temperature sensors “TS” may beprovided on the ablation catheter 14, e.g., adjacent the distalradiating section 42 (as shown in FIG. 5) and may be configured tomeasure tissue temperatures in or adjacent an ablation zone. Thetemperature monitoring system 3 can be, for example, a radiometrysystem, a thermocouple based system, or any other tissue temperaturemonitoring system known in the art. The temperature monitoring system 3may be incorporated into the energy source 16 to provide feedback to theenergy source, or alternatively be housed in a separate box providingaudible or visual feedback to the clinician during use of the ablationcatheter 14. In either embodiment, the temperature monitoring system 3may be configured to provide tissue temperature and ablation zonetemperature information to the energy source 16 (or other suitablecontrol system). In embodiments, temperature sensors 3 may be includedalong the coaxial cable 36, or along assembly 12 (described withreference to FIG. 1), or along the EWC 90 to provide a greater array oftemperature data collection points and greater detail on the temperatureof the tissue following application of energy.

In at least one embodiment, the tissue temperature and/or ablation zonetemperature information may be correlated to specific known ablationzone sizes or configurations that have been gathered through empiricaltesting and stored in one or more data look-up tables and stored inmemory of the temperature sensing monitoring system 3 and/or the energysource 16. The data look-up tables may be accessible by a processor ofthe temperature sensing monitoring system 3 and/or the energy source 16and accessed by the processor while the distal radiating section 42 isenergized and treating target tissue. In this embodiment, thetemperature sensors “TS” provide tissue temperature and/or ablation zonetemperature to the microprocessor which then compares the tissuetemperature and/or ablation zone temperature to the known ablation zonesizes stored in the data look-up tables. The microprocessor may thensend a command signal to one or more modules of the temperature sensingmonitoring system 3 and/or the energy source 16 to automatically adjustthe microwave energy output to the distal radiating section 42.Alternatively, a manual adjustment protocol may be utilized to controlthe microwave energy output to the distal radiating section 42. In thisembodiment, the microprocessor may be configured to provide one or moreindications (e.g., visual, audio and/or tactile indications) to a userwhen a particular tissue temperature and/or ablation zone temperature ismatched to a corresponding ablation zone diameter or configuration.

System 10, depicted in FIG. 1 is configured to treat tissue, and asfurther set forth in FIG. 7 enables a method of identifying targettissue (hereinafter simply referred to as “a target”) utilizing computedtomographic (CT) images, and once identified further enables the use ofa navigation or guidance system to place the catheter assembly 12 orother tools at the target. CT data facilitates the planning of a pathwayto an identified target as well as providing the ability to navigatethrough the body to the target location, this includes a preoperativeand an operative component (i.e., pathway planning and pathwaynavigation).

The pathway planning phase includes three general steps. The first stepinvolves using software for generating and viewing a three-dimensionalmodel of the bronchial airway tree (“BT”) and viewing the CT data toidentify targets. The second step involves using the software forselection of a pathway on the BT, either automatically,semi-automatically, or manually, if desired. The third step involves anautomatic segmentation of the pathway(s) into a set of waypoints alongthe path that can be visualized on a display. It is to be understoodthat the airways are being used herein as an example of a branchedluminal network. Hence, the term “BT” is being used in a general senseto represent any such luminal network (e.g., the circulatory system, orthe gastro-intestional tract, etc.)

Using a software graphical interface 64 as shown in FIG. 6, generatingand viewing a BT, starts with importing CT scan images of a patient'slungs into the software. The software processes the CT scans andassembles them into a three-dimensional CT volume by arranging the scansin the order they were taken and spacing them apart according to thesetting on the CT when they were taken. The software uses thenewly-constructed CT volume to generate a three-dimensional map, or BT,of the airways. The software then displays a representation of thethree-dimensional map 66 on the software graphical interface 64. A usermay be presented with various views to identify masses or tumors thatthe medical professional would like to biopsy or treat, and to which themedical professional would like to use the system 10 to navigate.

Next, the software selects a pathway to a target, e.g., target 68identified by a medical professional. In one embodiment, the softwareincludes an algorithm that does this by beginning at the selected targetand following lumina back to the entry point. The software then selectsa point in the airways nearest the target. The pathway to the target maybe determined using airway diameter.

After the pathway has been determined, or concurrently with the pathwaydetermination, the suggested pathway is displayed for user review. Thispathway is the path from the trachea to the target that the software hasdetermined the medical professional is to follow for treating thepatient. This pathway may be accepted, rejected, or altered by themedical professional. Having identified a pathway in the BT connectingthe trachea in a CT image with a target, the pathway is exported for useby system 10 to place a catheter and tools at the target for biopsy ofthe target and eventually treatment if necessary. Additional methods ofdetermining a pathway from CT images are described in commonly assignedU.S. patent application Ser. No. ______ having attorney docket no.H-IL-00087 (1988-00087) entitled “Pathway Planning System and Method”the entirety of which is incorporated herein by reference.

FIG. 7 shows a patient “P” lying on an operating table 70 and connectedto a system enabling navigation along the determined pathway within theluminal network to achieve access to the identified target. Abronchoscope 72 is inserted into the patient's lungs. Bronchoscope 72 isconnected to monitoring equipment 74, and typically includes a source ofillumination and a video imaging system. In certain cases, the devicesof the present disclosure may be used without a bronchoscope, as will bedescribed below. System 10 monitors the position of the patient “P”,thereby defining a set of reference coordinates. Specifically, system 10utilizes a six degrees-of-freedom electromagnetic position measuringsystem according to the teachings of U.S. Pat. No. 6,188,355 andpublished PCT Application Nos. WO 00/10456 and WO 01/67035, which areincorporated herein by reference. A transmitter arrangement 76 isimplemented as a board or mat positioned beneath patient “P.” Aplurality of sensors 78 are interconnected with a tracking module 80which derives the location of each sensor 78 in 6 DOF (degrees offreedom). One or more of the reference sensors 78 (e.g., 3 sensors 78)are attached to the chest of patient “P” and their 6 DOF coordinatessent to a computer 82 (which includes the software) where they are usedto calculate the patient coordinate frame of reference.

FIG. 8 depicts a positioning assembly 84, constructed and operativeaccording to the teachings of the present disclosure. Positioningassembly 84 includes a locatable guide 86 which has a steerable distaltip 88, an extended working channel 90 and, at its proximal end, acontrol handle 92.

There are several methods of steering the extended working channel 90.In a first method, a single direction of deflection may be employed.Alternatively, a multi-directional steering mechanism with a manualdirection selector may be employed to allow selection of a steeringdirection by the practitioner without necessitating rotation of thecatheter body. With multi-directional steering four elongated tensioningelements (“steering wires”) 98 a are implemented as pairs of wiresformed from a single long wire extending from handle 92 to distal tip88. Steering wires 98 a are bent over part of a base 98 b and return tohandle 92. Steering wires 98 a are deployed such that tension on eachwire individually will steer the distal tip 88 towards a predefinedlateral direction. In the case of four steering wires 98 a, thedirections are chosen to be opposite directions along two perpendicularaxes. In other words, the four steering wires 98 a are deployed suchthat each wire, when actuated alone, causes deflection of the distal tip98 in a different one of four predefined directions separatedsubstantially by multiples of 90°.

Locatable guide 86 is inserted into the extended working channel 90within which it is locked in position by a locking mechanism 94. Aposition sensor element 96 of system 10 is integrated with the distaltip 88 of the locatable guide 86 and allows monitoring of the tipposition and orientation (6 DOF) relative to the reference coordinatesystem.

In embodiments, locatable guide 86 may have a curved or hookedconfiguration as shown in FIG. 10. This alternative is currentlymarketed by Covidien LP under the name EDGE®. In such a system, it isthe extended working channel 90 that is formed with a curved tip 91.Differing amounts of pre-curve implemented in the extended workingchannel 90 can be used, however, common curvatures include 45, 90, and180 degrees. The 180 degree extending working channel 90 has been foundparticular useful for directing the locatable guide 86 to posteriorportions of the upper lobe of the lung which can be particularlydifficult to navigate. The locatable guide 86 is inserted into theextended working channel 90 such that the position sensor 96 projectsfrom the distal tip 88 of the extended working channel 90. The extendedworking channel 90 and the locatable guide 86 are locked together suchthat they are advanced together into the lung passages of the patient“P.” In this embodiment, the extended working channel 90 may include asteering mechanism similar to the one already described above. As can beappreciated, certain modifications may need to be made to the extendedworking channel 90 in order for the extended working channel to functionas intended.

In embodiments, an integrated radial ultrasound probe “US” (FIG. 10) maybe provided on the extended working channel 90, the locatable guide 86,catheter assembly 12 and/or the ablation catheter 14. For illustrativepurposes, the ultrasound probe “US” is shown disposed on the extendedworking channel 90 and the locatable guide 86. The ultrasound probe “US”may be configured to provide ultrasound feedback to one or more modulesof the system 10 during navigation and insertion of the ablationcatheter 14 to facilitate positioning the ablation catheter 14 adjacenttarget tissue. As will be appreciated a US probe may also be usedwithout the extended working channel but in conjunction with anendoscope for imaging central lesions that would be accessible to theendoscope. Furthermore, the US probe may be used to monitor treatmentprogression and/or confirm treatment completion.

As noted above, the present disclosure employs CT data (images) for theroute planning phase. CT data is also used for the navigation phase.Specifically, the CT system of coordinates is matched with the patientsystem of coordinates; this is commonly known as registration.Registration is generally performed by identifying locations in both theCT and on or inside the body, and measuring their coordinates in bothsystems. Manual, semi-automatic or automatic registration can beutilized with the system 10. For purposes herein, the system 10 isdescribed in terms of use with automatic registration. Reference is madeto commonly assigned U.S. patent application Ser. No. 12/780,678, whichis incorporated herein by reference, for a more detailed description ofautomatic registration techniques.

The automatic registration method includes moving locatable guide 86containing position sensor 96 within a branched structure of a patient“P.” Data pertaining to locations of the position sensor 96 while theposition sensor 96 is moving through the branched structure is recordedusing the transmitter arrangement 80. A shape resulting from the data iscompared to an interior geometry of passages of the three-dimensionalmodel of the branched structure. And, a location correlation between theshape and the three-dimensional model based on the comparison isdetermined.

In addition to the foregoing, the software of the system 10 identifiesnon-tissue space (e.g. air filled cavities) in the three-dimensionalmodel. Thereafter, the software records position data of the positionsensor 96 of the locatable guide 86 as the locatable guide 86 is movedthrough one or more lumens of the branched structure. Further, thesoftware aligns an image representing a location of the locatable guide86 with an image of the three-dimensional model based on the recordedposition data and an assumption that the locatable guide 86 remainslocated in non-tissue space in the branched structure.

Once in place in the patient “P,” a screen 93 will be displayed by thesoftware on the monitoring equipment 74 (FIG. 11). The right image isthe actual bronchoscopic image 95 generated by the bronchoscope 72.Initially there is no image displayed in the left image 97, this will bea virtual bronchoscopy generated from the CT image data onceregistration is complete.

Starting with the locatable guide 86, and specifically the positionsensor 96 approximately 3-4 cm above the main carina, as viewed throughthe bronchoscope 72, the bronchoscope 72 is advanced into both the rightand left lungs to, for example, the fourth generation of the lungpassages. By traversing these segments of the lungs, sufficient data iscollected as described above such that registration can be accomplished.

Now that the targets have been identified, the pathway planned, thebronchoscope 72 including locatable guide 86 inserted into the patient“P,” and the virtual bronchoscopy image registered with the image dataof the bronchoscope 72, the system 10 is ready to navigate the positionsensor 96 to the target 68 within the patient's lungs. The computer 80provides a display similar to that shown in FIG. 11 identifying thetarget 68 and depicting the virtual bronchoscopy image 99. Appearing ineach of the images on the display is the pathway from the currentlocation of the position sensor 96 to the target 68. This is the pathwaythat was established during the pathway planning phase discussed above.The pathway may be represented, for example, by a colored line. Alsoappearing in each image is a representation of the distal tip 88 of thelocatable guide 86 and position sensor 96. Once the pathway isestablished, a clinician may utilize system 10 to treat the targettissue 68.

Operation of the system 10 to treat target tissue is described withreference to FIGS. 12A-16C. It is assumed the pathway to the target 68had been ascertained via the methods described above. After, advancingthe bronchoscope 72 including the extended working channel 90 and thelocatable guide 86 to a point of being wedged within the luminalnetwork, the extended working channel and locatable guide are furtheradvanced along the identified pathway to the target 68 (see FIGS.12A-12C).

In some cases the target tissue may be directly accessed from within thelumen (such as for the treatment of the endobronchial wall for COPD,Asthma, lung cancer, etc.), however in other instances, the target isnot in direct contact with the BT and use of the locatable guide alonedoes not achieve access to the target. Additional access tools may berequired to cross the lumen and access the target tissue (such as forthe treatment of disease within the parenchyma).

Final localization and confirmation of the locatable guide or accesstool with extended working channel may be performed with imaging and/ornavigational guidance (this may include the same or differentcombinations of imaging and navigation techniques listed above).

Once the locatable guide 86 or an additional access tool hassuccessfully been navigated to the target 68 location, the locatableguide 86 or access tool may be removed, leaving the extended workingchannel 90 in place as a guide channel for a biopsy tool 84 to thetarget 68 location (FIGS. 13A-13B). The medical tools may be biopsytools that can be used to sample the target 68. Details of this systemare included in U.S. Pat. No. 7,233,820, already incorporated herein byreference.

Once the locatable guide 86 has successfully been navigated to thetarget 68 location, the locatable guide 86 may be removed, leaving theextended working channel 90 in place as a guide channel for bringing atool 84 to the target 68 location (FIGS. 13A-13B). The medical tools maybe biopsy tools that can be used to sample the target 68. These samplesare retrieved and sent to pathology for analysis to determine iftreatment of the target is necessary. The biopsy analysis can happen inreal time after the biopsy procedure such that the ablation can beperformed immediately, or there can be some period of time, e.g., hours,days, weeks, between the time when the biopsy is taken and when theablation procedure is performed.

If it is determined that the target 68 requires treatment (e.g.,ablation), the assembly 12 including the ablation catheter 14 may bepositioned through the bronchoscope 72 and the extended working channel90 to enable treatment. Placement of the assembly may occur after theextended working channel 90 has been navigated to the target 68, or theextended working channel 90 may be navigated with the assembly 12 toreach the target 68. This second option may require a sensor providing 6DOF positioning within either the extended working channel 90 or theassembly 12. As noted above, the braided configuration of the outerconductor 48 and the conductive layer 51 of the balun 52 in combinationwith the lumen configurations depicted in FIGS. 2-3, provides theassembly 12 with the needed flexibility to move within the relativelynarrow airways.

In embodiments, the target tissue “T” may be pierced or penetrated toallow placement of the distal radiating section 42 within the target 68(e.g., centered within the mass for treatment). For example, a guidewire, piercing tool, a biopsy tool 84 or the distal end 21 of theassembly 12 (described with reference to FIG. 1) may be utilized topierce or penetrate the target 68. In the instance where the guide wireor piercing tool is utilized to penetrate or pierce tissue, the guidewire or piercing tool may passed through the extended working channel 90to penetrate the target 68. Once pierced, the extended working channel90 may be held in place and the guide wire or piercing tool removed toallow the assembly 12, housing the ablation catheter 14, to be insertedinto the opening created by the tool or the guide wire in the target 68.Alternatively, while the guide wire or piercing tool is in the target68, the extended working channel 90 may be extended to place the distalend of the extended working channel 90 within the opening created in thetarget 68. Following placement of the extended working channel 90 withinthe target 68, the guide wire or piercing tool can be removed to allowfor insertion of the assembly 12 including ablation catheter 14. Thissecond method helps assure proper placement of the ablation catheter 14,housed within the assembly 12, into the target 68.

One or more imaging modalities may be utilized to confirm that theablation catheter 14 has been properly positioned (e.g. within thetarget 68.) For example, computer tomography (CT), ultrasound,fluoroscopy, and other imaging modalities may be utilized individuallyor in combination with one another to confirm that the ablation catheter14 has been properly positioned within the target 68. One methodologyemploying both CT and fluoroscopy imaging modalities is described incommonly assigned U.S. application Ser. No. 12/056,123 entitled“CT-Enhanced Fluoroscopy,” the contents of which is incorporated hereinby reference.

Yet a further alternative method of ablation catheter 14 placementconfirmation is disclosed herein. FIG. 46A represents a livefluoroscopic image depicting the placement of an extended workingchannel 90 and an ablation assembly 12 or biopsy tool 84 extendingtherefrom, after performing one of the navigation procedures describedherein. FIG. 46B is a virtual fluoroscopic image depicting the samepatient and displaying a target 68 thereon. The virtual fluoroscopicimage is generated from the same CT data used in both the planning andnavigation methods described above. The CT data is manipulated to createa computer model of a fluoroscopic image of the patient. The target 68is the same target 68 identified in the planning phase, and the locationof the target 68 in the virtual fluoroscopic image corresponds to thelocation of the target identified by the clinician during planning.

The virtual fluoroscopic image and the live fluoroscopic image may beregistered to one another. This may be done using, for example, one ormore fiducial markers placed either prior to the CT scan and that willalso appear on the fluoroscopic image, or by identifying landmarkswithin the physiology that may act as fiducial markers (e.g., curvatureand spacing of the rib cage). The two images, the live fluoroscopicimage and the static virtual fluoroscopic image provide the clinicianwith the ability to compare placement of the extended working channel 90and the ablation assembly 12 with the location of the target 68. Thismay be done in either a side by side comparison mode as shown in FIGS.46A and 46B. For example, in FIG. 46A, the live fluoroscopic image, amass 67 that has been identified as the target 68 during the planningphase may only be lightly visible under fluoroscopy, often soft tissueis difficult to discern in fluoroscopic images, but by comparing thelocation of the extended working channel 90 and the ablation assembly 12as shown in FIG. 46A to the location of the target 68 shown in FIG. 46B,the necessary adjustments to positioning for proper ablation can bereadily ascertained.

Alternatively, where the live and the virtual fluoroscopic images areregistered to one another, comparison may be made by overlaying thevirtual image (FIG. 46B) over the live image (FIG. 46 A) such that acomposite image is created. This composite image then depicts therelative position of the target 68 to the placement of the ablationassembly 12 and extended working channel 90. By continuing livefluoroscopy visualization of the placement of the extended workingchannel 90 and/or the ablation assembly 12, or a biopsy tool 84 into thetarget 68 is enabled, thus enabling the clinician to actually see theproper placement into a target 68 in real time using a combination of alive fluoroscopic image and an overlaid virtual fluoroscopic image. Onceplacement of the ablation catheter 14 is confirmed within the target 68,microwave energy can be transmitted to the ablation catheter 14 to treatthe target 68.

Following treatment of the target 68, one of the aforementioned imagingmodalities may be utilized to confirm that a suitable ablation zone hasbeen formed around the target 68 and to determine whether additionalapplication of energy are necessary. These steps of treating and imagingmay be repeated iteratively until a determination is made that thetarget has been successfully ablated. Moreover, the methodologydescribed above using the imaging modalities to confirm the extent oftreatment and determine whether additional application of energy isnecessary can be combined with the radiometry and temperature sensingtechniques described above to both confirm what is depicted by theimaging modality and to assist in determining treatment cessationpoints.

In an embodiment, such as, for example, when the target 68 is relativelyclose to a distal end of the bronchoscope 72, the extended workingchannel 90 may be removed (FIG. 14), or not used at all, and thebronchoscope 72 kept in place to visually guide access tools and theassembly 12 including the ablation catheter 14 to target 68.Alternately, the extended working channel 90 and accompanying accesstools may be placed without use of the bronchoscope 72, or thebronchoscope 72 can be removed after placement of the extended workingchannel 90 in combination with access tools at the target 68 and kept inplace and the assembly 12 including the ablation catheter 14 can beextended through the extended working channel 90 to treat the target 68.

As noted above, temperature monitoring system 3 can be used to determineand monitor temperature of the target tissue 68, ablation zone size,etc. In embodiments, the temperature monitoring system 3 canincorporated into one or more components (e.g., software graphicalinterface 64) that are configured for use with the system 10.

In embodiments, placement of the extended working channel 90 and/or theablation catheter 14 within the luminal network may accomplished withoutthe use of the aforementioned pathway planning and pathway navigationmethods. In this instance, computer tomography, ultrasound and/orfluoroscopy mat be utilized to facilitate positioning the extendedworking channel 90, and/or access tools and/or the ablation catheter 14within the luminal network.

In embodiments, the distal radiating section 42 may be covered by atemperature sensitive “wax” material “W” that melts when energy isapplied to the inner conductor 20, thereby absorbing heat from thedistal radiating section 42 by changing phase.

Moreover, in place of fluid cooling the distal radiation section 42 maybe frozen to create an ice formation therearound. When the distalradiating section is energized, the ice turns to gas which may result inhigh heat dissipation, which, in turn, cools the distal radiatingsection 42.

Further, in accordance with the instant disclosure, it may proveadvantageous to utilize the ablation catheter 14 without the assembly12. In this particular embodiment, the extended working channel 90 maybe modified to provide for fluid cooling of the ablation catheter 14,for example one of the aforementioned lumen and port configurations anda closed distal tip. As can be appreciated, one or more othermodifications may also have to be made to the extended working channel90 in order for the extended working channel 90 to function as intendedherein.

FIGS. 15A-15B illustrate an extending working channel 190 having aclosed distal end and a modified catheter assembly 12 inserted therein.Rather than a closed distal end as shown in FIG. 1, the catheterassembly 12 has an open distal end. A space between the inner surface ofthe extended working channel 190 and the catheter assembly 12establishes a fluid inflow lumen 119 a. A fluid outflow lumen 119 c isexposed by the opening of the distal end of the catheter assembly 12.The lumens 119 a and 119 c allow for cooling fluid to flow in theextended working channel 190 and catheter assembly 12 to cool an theablation catheter 14 located within the catheter assembly 12. A crosssection of the extended working channel 190 with modified catheterassembly 12 is shown in FIG. 16D. The catheter assembly 12 mayoptionally include a position sensor 96 such that the catheter assembly12 acts as a locatable guide 86 (FIG. 12) to assist in the positioningof the extended working channel at a target 68. The extended workingchannel 190 may be formed to meet the flexibility criteria describedabove. Alternatively, the extended working channel may be placed asdescribed above using a locatable guide 86 Thereafter, the locatableguide 86 may be removed and the extended working channel 190 kept inplace. With the locatable guide 86 removed, the modified catheterassembly 12 and ablation catheter 14 may be positioned within theextended working channel 190 (FIG. 16A) and energized to form anablation zone “AB” suitable for treating target 68 (FIG. 16B). FIG. 16Cshows yet another optional configuration, where the ablation catheter 14is placed into the extended working channel 190 without any assemblyfollowing placement of the extended working channel 190 and removal ofthe locatable guide 86. Water may be circulated within the extendedworking channel 190 to cool the distal radiating section in a manner asdescribed above.

As can be appreciated, a result of the flexible assembly 12 includingthe ablation catheter 14 being inserted endobrachially is that thelikelihood of pneumothoraces occurring is greatly reduced by navigatingthrough the luminal branches of the lung. Moreover, the ability of thesystem 10 to create a pathway to target tissue takes the guess work outof positioning the locatable guide, the extended working channel and theassembly 12 including the ablation catheter 14.

From the foregoing and with reference to the various figure drawings,those skilled in the art will appreciate that certain modifications canalso be made to the present disclosure without departing from the scopeof the same. For example, one or modifications may be made in the way ofdevice delivery and placement; device cooling and antenna buffering; andsensor feedback. The following are a variety of non-limiting examples ofsuch modifications considered within the scope of the presentdisclosure.

I. Device Delivery and Placement

In accordance with the instant disclosure, various methods may beutilized to deliver the ablation catheter 14 and/or the extended workingchannel 90/190 into a desired location in the target tissue 68.

For example, to address the occurrence of bleeding within the patient asa result of biopsy or ablation, the bronchoscope may be employed tocreate tamponade; that is, the bronchoscope can be wedged into thebronchus to stop the bleeding at points the bronchoscope can reach.However, in accordance with the instant disclosure, the extended workingchannels 90/190 could be navigated to the target 68 and one or moreexpandable members may be provided on the extended working channels90/190 to create tamponade. The expandable member, e.g., a balloon, canbe inflated to stop bleeding at these remote locations.

Specifically, FIGS. 17 and 18 illustrate the extended working channels90/190 including a balloon “B” that is positioned on an exterior surfaceof the extended working channels 90/190. The balloon “B” is initially ina deflated configuration (FIG. 17) for navigating the extended workingchannel 90/190 through a conductive airway and positioning the extendedworking channels 90/190 adjacent the target 68. Subsequently, theballoon is inflated for anchoring the extended working channel 90/190 inplace and to create a tamponade (FIG. 18).

In the embodiment where the balloon “B” is provided on the extendedworking channel 90, one or more lumens may be provided on the extendedworking channel 90 and may be in fluid communication with the balloon“B” to provide one or more suitable fluids from the fluid source 32 tothe balloon “B” to move the balloon “B” from the inflated configurationto the deflated configuration (and vice versa). Moreover, in thisembodiment, the balloon “B” may be configured to control local lungproperties which change with respiration. For example, the relativepermittivity of deflated lung tissue at 2450 MHz is 48 and the relativepermittivity of inflated lung tissue at the same frequency is 20; thislarge permittivity range makes it difficult to tune an antenna to asingle frequency. It has been found through empirical testing that byadding the balloon “B,” the lung can be locally isolated during aninflated or deflated state to produce one or more desired properties,e.g., electrical and thermal. Specifically, thermal conductivity changeswith inflation and deflation of the lungs. For example, if localrespiration was stopped with the lung inflated and the ablation catheter14 was matched to the target 68 with a relative permittivity of 45,heating can be focused thermally and electrically to the target 68.Likewise, if the lung were fixed in a deflated configuration, more lungtissue could be thermally treated to produce additional margin aroundthe target 68.

FIGS. 19A-19B illustrate an ablation catheter 214 according to anotherembodiment of the present disclosure. Ablation catheter 214 is similarto ablation catheter 14. Accordingly, only those features unique toablation catheter 214 are described in detail. An expandable balun 252is provided on a coaxial cable 236. The balun 252 functions in a manneras described above with respect to the balun 52. Unlike balun 52,however, the balun 252 is expandable (air/fluid pressure) and configuredto provide the functions of the balloon “B” as described above.

One or more lumens (not shown) may be provided on the ablation catheter214 and configured to receive one or more suitable fluids from the fluidsource 32 to move the balun 252 between the deflated and inflatedconfigurations, see FIGS. 19A-19B. Alternatively, the lumens 19 a, 19 cof the assembly 12 may be in fluid communication with the balun 252 andconfigured to provide one or more suitable fluids from the fluid source32 to the balun 252 to move the balun 252 between inflated and deflatedconfigurations. As can be appreciated, other methods and/or devices maybe utilized to move the balun 252 between inflated and deflatedconfigurations.

FIG. 20 illustrates an extended working channel 290 according to anotherembodiment of the instant disclosure. In this embodiment, a closeddistal tip 291 is energizable for penetrating tissue “T.” Specifically,an electrode 292 may be coupled at the distal tip 291 of the extendingworking channel 290. The electrode 291 may be in electricalcommunication with the energy source 16 via one or more leads or wires293 that extend within the extended working channel 290. The electrode292 may be configured for monopolar operation. A return pad (not shown)may be positioned on a patient and utilized as a return electrode.Alternatively, a second electrode (not shown) can be provided on theextended working channel 290 to create a bipolar electrodeconfiguration. In use, when the electrode 291 is energized, the distaltip 291 may be utilized to penetrate tissue to facilitate positioningthe extended working channel 290 adjacent target tissue.

FIG. 21 illustrates an extended working channel 390 according to anotherembodiment of the instant disclosure. The extended working channel 390includes a closed distal end and at least one water filled lumen orchamber (e.g., a lumen 319 a of the cooling water loop utilized to coolthe distal radiating section 42) that includes a piston assembly 321including a base 323 and a needle 325 extending distally from the baseand through an aperture (not shown) at a distal end of the lumen 319 a.A seal (not shown) may be provided within the aperture of the lumen 319a to maintain the pressure within the lumen. An optional seal 327 may beprovided at a distal tip of the extended working channel 390 and may beconfigured to maintain a fluid tight seal. The piston assembly 321 ismovable within the lumen 319 a to move the needle 325 from a retractedconfiguration to an extended configuration (shown in phantom in FIG. 21)through the seal 327. In the extended configuration, the needle 325 maybe utilized to anchor the extended working channel 390 to tissue and/orpenetrate tissue.

In use, water may be provided to the extended working channel 390 tomove the needle 325 to the extended configuration for penetratingtissue; this may be done prior to energizing the distal radiatingsection 42 and/or when the distal radiating section 42 is energized.Thus, the cooling water loop serves a dual purpose (cooling of thedistal radiating section and extension of the needle 325) and mayeliminate the need for a separate push/pull member or sheath.

FIG. 22 illustrates an extended working channel 490 according to anotherembodiment of the instant disclosure. The extended working channel 490includes an open distal end and an electrode 492 operably coupledthereto. Electrode 492 is similar to the electrode 292 illustrated inFIG. 20. Unlike electrode 292, however, electrode 492 may extend alongan outer peripheral surface of the extended working channel 490.Additionally, a pair of upright electrode extensions 494 a. 494 b may beprovided on the electrode 492 and configured to function as a monopolarpencil to treat tissue.

The electrode 492 may be in electrical communication with the energysource 16 via one or more leads or wires 493 that extend within theextended working channel 490. The electrode 492 may be configured formonopolar operation. A return pad (not shown) may be positioned on apatient and utilized as a return electrode. Alternatively, a secondelectrode (not shown) can be provided on the extended working channel490 to create a bipolar electrode configuration. In use, after tissuehas been ablated, the upright extensions 494 a, 494 may be utilized totransmit microwave energy (or RF) to neighboring tissue. After thetissue has been treated, the upright extensions 494 a, 494 b may beutilized to scrape the electrosurgically treated tissue. As can beappreciated, having the electrode 492 on the extended working channel490, allows a user to treat tissue with the electrode 492 while leavingablation catheter 14 in place within the extended working channel 490.

FIG. 23 illustrates a head-up display 81 (e.g., Google glasses) thatcommunicates with the guidance system for providing a virtual internalimage to a clinician. The virtual internal image includes informationpertaining to planning the pathway to the target 68 and for guiding andnavigating one of the aforementioned tools, extended working channelsand the locatable guides through the lungs of a patient “P.” The head-updisplay 81 may include one or more electromagnetic sensors 83 forproviding a position of the head-up display 81 relative to a patient “P”for projecting the virtual internal image into a clinician's view of thepatient “P” with the proper orientation.

II. Device Cooling and Antenna Buffering

The following embodiments are configured to protect a patient fromunintended heating from the coaxial cable 36 and/or the distal radiatingsection 42 and/or configured to provide dielectric buffering to thedistal radiating section 42.

FIGS. 24-26 illustrate an assembly 512 according to an embodiment of theinstant disclosure. Assembly 512 is similar to assembly 12. Accordingly,only those features unique to assembly 512 are described in detail.

A partition 511 is provided within the housing 523 adjacent the distalend of the assembly 512 to provide a chamber 514 that is configured toisolate the distal radiating section 542 from the rest of the coaxialcable 536. A dielectric (e.g. ceramic, hydrogel, etc.) 513 is providedwithin the chamber 514 to cover the distal radiating section 542 and isconfigured to cool the distal radiating section 542 and the innerconductor 540 when contacted by fluid being transmitted through thelumens 519 a, 519 c and into contact with the partition 511. Inaccordance with the instant disclosure, the dielectric 513 is capable ofwithstanding heat without changing properties to buffer the distalradiating section 542 and create a separate active cooling system aroundthe coaxial cable 536. This reduces, if not eliminates, phase changesaround the distal radiating section 542 during activation thereof andmay reduce the active cooling requirements on the coaxial cable 536.

FIG. 27 illustrates an assembly 612 according to an embodiment of theinstant disclosure. A plurality of ceramic elements 613 extend at leastpartially along the coaxial cable 636 and form a nested configuration.The ceramic elements 613 serve as a heat sink to cool a distal radiatingsection 642 and an inner conductor 640. The ceramic elements 613 may beactuatable to move from a relaxed configuration wherein the plurality ofceramic elements 613 are spaced apart from one another (as shown in FIG.27) to allow the coaxial cable 636 to flex, to a compressedconfiguration wherein the ceramic elements 613 are moved towards oneanother to increase cooling of the distal radiating section 642 and theinner conductor 640, and to secure the position of the location of theassembly. A pair pull wire 617 operably couples to the ceramic elements613 and is configured to move the ceramic elements 613 to the compressedconfiguration.

FIG. 28 illustrates an extended working channel 790 according to anembodiment of the instant disclosure. The extended working channel 790functions as a structural thermal sink that is configured to sink heateither by itself or in conjunction with a cooling fluid. In theembodiment illustrated in FIG. 28, the extended working channel 790 isformed from a material that is a good thermal conductor to pull awayheat from the distal radiating section 742. A heat sink 791 is operablycoupled to a proximal end 793 of the extended working channel 790. Forexample, lumens 719 a, 719 c (shown in phantom) extend to a proximal endof a balun 752 to cool the proximal end 793 of the extended workingchannel 790. In this particular embodiment, the fluid may flow up to theproximal end of the balun 752 and turn around; this would keep theextended working channel 790 cool at the proximal end 793. Conduction isutilized to move cool air through a distal end of the extending workingchannel 790 distal to the balun 752 to the cooled proximal end 793 ofthe extended working channel 790 proximal to the balun 752. Additionallyor alternatively, a ceramic paste “CP” may at least partially cover thedistal radiating section 742 and may serve as a dielectric buffer toprovide static cooling of the distal radiating section 742. Use of theceramic paste “CP” may allow the extended working channel 790 to beformed without the lumens 719 a, 719 c, which, in turn, would allow theextended working channel 790 to remain flexible while providing staticcooling and/or buffering.

FIG. 29 illustrates an extended working channel 890 according to anembodiment of the present disclosure. By using a vacuum pump to pullwater through a the extended working channel 890, the boiling point ofthe water circulating through the extended working channel 890 can belowered. At this pressure water boils at about body temperature and theboiling water will rapidly vaporize and the change of phase results incooling of the fluid and components adjacent to it and create anadditional cooling effect for an ablation catheter 814. To this end, avacuum pump 33 operably couples to a fluid return port (not shown) onthe extended working channel to pressurize a fluid circulating throughlumens 819 c for lowering a boiling point of the fluid circulatingthrough the lumens 819 c. In embodiments, an air-mist mixture may beutilized as the cooling medium and circulated through the lumens 819 a,819 c; this embodiment takes advantage of the large energy needed tochange phase from liquid to vapor, even where temperature remainsconstant.

FIG. 30 illustrates an extended working channel 990. The extendedworking channel 990 may include a two lumen configurations (notexplicitly shown). In this embodiment, one lumen is dedicated forcommunication with a fluid intake port (not shown) of the extendedworking channel 990 and one lumen dedicated to support the ablationcatheter 914. Unlike the previous disclosed lumen configurations, thefluid intake port and the lumen are configured for an open loop coolingprotocol. The open loop cooling protocol may improve fluid flow withinthe extended working channel 990. Moreover, energy delivery andmicrowave energy absorption may be improved by hydrating the target.Further, the open loop cooling protocol may be combined with expandableballoon “B” and/or expandable balun 252 to lock the extended workingchannel 990 in place, which, in turn, may increase dielectric bufferingaround the distal radiating section 942.

In embodiments, the extended working channel 990 may include a fluidreturn port and a corresponding third lumen that is configured toprovide suction for suctioning the cooling fluid dispensed from theextended working channel 990; this may provide a user with the abilityto perform a Bronchoalveolar Lavage (BAL) at the end of the microwaveablation procedure, i.e., by stopping fluid flow and sucking the fluidback to retrieve one or more tissue samples.

FIGS. 31-32 illustrate an extended working channel 1090 according toanother embodiment of the present disclosure. In this embodiment, theextended working channel 1090 may be utilized as a thermal andelectrical control by extending the distal radiating section 1042through a seal structure 1091 that is provided at a distal end of theextended working channel 1090. The seal structure 1091 is configured forsealed engagement with the distal radiating section 1042 to maintain afluid tight seal when the distal radiating section 1042 is extendedtherethrough for treating tissue.

FIG. 33 illustrates an extended working channel 1190 according toanother embodiment of the present disclosure. In this embodiment, noflow fluid buffering is utilized to cool the distal radiating section1142. With this purpose in mind, a chamber 1191 is provided at a distalend of the extended working channel 1190 and is not in fluidcommunication with lumens 1119 a, 1119 c. The chamber 1191 surrounds thedistal radiating section 1142 and is configured to receive a highboiling point liquid (e.g., water, saline, etc.) being therein to coolthe distal radiating section 1142. In this embodiment seal members 1121a, 1121 b may be optionally provided at distal ends of the lumens 1119a, 1119 c and are configured to maintain the high boiling point liquidwithin the chamber 1191. The higher boiling point liquid in chamber 1191absorbs heat generated by the distal radiating section 1142 andtransfers it to the fluid circulated through lumens 1119 a and 1119 c.

FIGS. 34 and 35 illustrate an extended working channel 1290 according toanother embodiment of the instant disclosure. In this embodiment, a heatsink 1291 having an accordion configuration is coupled to a distal endof the extended working channel 1290. The heat sink 1291 is configuredto couple to the distal radiating section 1242 via one or more suitablecoupling methods when the distal radiating section 1242 is extendedthrough the extended working channel 1290. In the illustratedembodiment, for example, a seal (not shown) may be provided at a distalend of the extended working channel 1290 and may be configured toreleasably engage (via a press or friction fit) the distal radiatingsection 1242 as the distal radiating section is extended from theextended working channel 1290 (FIG. 34). As the heat sink heats, itbegins to extend distally away from the extended working channel 1290bringing the distal radiating section 1242 coupled thereto with it. Inthe extended configuration, the distal radiating section 1242 will havebeen moved away from surrounding tissue, which, in turn, may reducecollateral damage to the surrounding tissue (FIG. 35).

FIGS. 36A and 36B illustrate an ablation catheter 1314 according to anembodiment of the instant disclosure. In the embodiment illustrated inFIGS. 36A and 36B, a heat sink is created with the walls of a lung(“LW”), which, typically, include a temperature in the range of about37° C. To this end, a thermally conductive balloon 1321 is positionedadjacent a distal radiating section (not explicitly shown) of theablation catheter 1314 and is expandable (via one or more of theaforementioned lumen configurations) to dissipate heat from the distalradiating section into the wall of a lung “LW” of patient. Specifically,when the distal radiating section is energized, the conductive balloon1321 is inflated and expands into contact with the wall of the lung“LW,” which, in turn sinks the heat absorbed by the thermally conductiveballoon 1321.

Alternatively, a plurality of thermally conductive fins 1323 (FIGS.37A-37B) may be positioned adjacent the distal radiating section. Inthis embodiment, the fins 1323 are expandable to absorb and dissipateheat from the distal radiating section when the distal radiating sectionis energized. In the embodiment illustrated in FIGS. 37A-37B, the fins1323 are formed from a shape memory metal that is configured to move toan expanded configuration when heated as a result of the distalradiating section being energized. Once expanded, airflow may beintroduced into the bronchus and across the plurality of thermallyconductive fins 1323 to cool the conductive fins 1323, which, in turn,will cool the distal radiating section.

FIG. 38 illustrates an extended working channel 1490 according to anembodiment of the instant disclosure. In this embodiment, the extendedworking channel 1490 includes a proximal end 1491 including a diameter“D1” that is larger than a tapered distal end 1492 that includes adiameter “D2.” The larger diameter D1 of the proximal end 1491 allowsfor more cooling for a given length of extended working channel 1490. Inaccordance with the instant disclosure, the diameter “D1” of theproximal end 1491 should be large enough to minimize coolant pressuredrop but small enough to fit in airways.

FIGS. 39A-39B illustrate an ablation catheter 1514 according to anembodiment of the instant disclosure. Specifically, a balloon 1515 maybe positioned adjacent the radiating section 1542 (and/or the balun notshown) and may be in fluid communication with the lumens (not explicitlyshown) within the ablation catheter 1514. The balloon 1515 is movablefrom a deflated configuration (FIG. 39A) for extending the ablationcatheter 1514 through an extended working channel 1590 to an inflatedconfiguration (FIG. 39B). In the inflated configuration, the balloon1515 may serve to expand a buffering volume, i.e., there is more volumeto heat. Moreover, the balloon 1515 may be configured to anchor thedistal radiating section 1542 in an airway of the lung. Further, theballoon 1515 may be configured to increase flow rate around the balun ofthe ablation catheter 1514.

III. Sensor Feedback

The following embodiments are configured to provide sensor and/or visualfeedback to the system 10 or physician relating device placement (e.g.,the extended working channel 90/190, the catheter assembly 12 and/or theablation catheter 14), tissue environment, ablation progress, deviceperformance, safety, etc.

In accordance with the instant disclosure, one or more feedbackmechanisms may be utilized with the instant disclosure. For example,FIGS. 40A-40B illustrate various fiducial markers that may be detectableby the system 10. Any of the aforementioned extended working channelsthat include an open distal end, e.g., the working channel 90, may beutilized as a conduit for the placement of one or more fiducial markerswithin the patient following removal of the locatable guide 86. Thesemarkers can be used for a variety of purposes including identifyingtumors and lesions for follow-up analysis and monitoring, to identifylocations that biopsy sampling has been undertaken, and to identify theboundaries or the center of a tumor or lesion for application oftreatment. Other uses will be understood by those of skill in the art asfalling within the scope of the present disclosure.

In embodiments, the fiducial markers may be formed from a shape memoryalloy “SM.” In this embodiment, the fiducial markers “SM” are configuredto change shape when heated to a predetermined temperature. Additionallyor alternatively, the fiducial markers may be formed from poloxamers“PM.” Poloxamers can be transformed from liquid to solid using energyfrom the distal radiating section of the ablation catheter, e.g., distalradiating section 42. Once in the body, the fiducial markers “PM” coolto body temp and transform back to liquid and are dissolved in thebloodstream. In solid form, the fiducial markers “PM” may be visibleunder CT, ultrasound, and other imaging modalities to reveal the realtime growth of the ablation zone “AZ.”

FIG. 41 illustrates another feedback mechanism that may be utilized withthe system 10. In this embodiment, a guide wire 73 that is positionablewithin one of the aforementioned extended working channels (e.g., theextended working channel 90) and deployable therefrom may be utilizedfor measuring a temperature of the aforementioned distal radiatingsections (e.g., distal radiating section 42). The guide wire 73 includesat least one thermocouple 75 at a distal end thereof. The thermocouples75 may be configured to capture temperature measurements when deployedfrom the extended working channel. The thermal couples 75 may be incommunication with a microcontroller of the energy source 16 to monitorrate of change of the temperature of or surrounding the distal radiatingsection 42; the rate of change can be analyzed to correlate with aspecific ablation size. In embodiments, the guide wire 73 may beutilized to deploy the ablation catheter 14 from the extended workingchannel 90.

FIGS. 42-43 illustrate another feedback mechanism that may be utilizedwith the system 10. In the embodiment illustrate in FIG. 42, the system10 is capable of detecting placement of an ablation catheter 1642 inhealthy vs. tumor tissue or if bleeding occurs along the ablationcatheter 1642. With this purpose in mind, one or more electrodes 1641(two electrodes 1641 shown in FIG. 42) are provided adjacent a distalradiating section 1642 and are configured to detect data pertaining tothe target tissue prior to, during or after activation of the distalradiating section 1642. The data pertaining to tissue may includeelectrical properties of the tissue, e.g., RF impedance.

In embodiments, the electrodes 1641 can be utilized to capturedielectric measurements of the surrounding tissue to ensure placement intumor tissue. The amount and type of buffering of the distal radiatingsection 1642 will play a role in how well the electrodes 1641 cancapture these measurements. With either of the RF or dielectricmeasurement types, a controller 17 (or another system 23, e.g., alaptop) connected to the ablation catheter 1614 will be needed tocapture and analyze the data to interpret to the user. After the data isanalyzed, the controller 17 provides the relevant information to a user,e.g., on a display 37.

In embodiments, the controller 17 may be configured to performS-parameter (FIG. 43) analysis between input and output ports of themicrowave energy source. In this embodiment, the S-parameter analysis isutilized to determine ablation size “AZ”, to control operation of theenergy source 16 and/or to detect damage to the distal radiating section1642 in real-time.

In embodiments, one or more sensor configurations may be utilized withthe system 10. For example, a hydration sensor “HS” (see FIG. 43 forexample) may be utilized to measure the water content of the tissue atsome distance from distal radiating section 42 to monitor ablationprogress and/or completion. In this instance, the extended workingchannel 90 may be utilized to position the “HS” at a predetermined pointaway from where the distal radiating section 42 is going to bepositioned. As moisture is driven out of the tissue, the sensor “HS”tracks the rate of change and can tell the user when the ablation iscomplete. Dielectric properties can be directly correlated withhydration levels of the tissue.

Moreover, one or more fiber optic cables “FC” may through the extendedworking channel 90 for positioning adjacent to target tissue forproviding a visual perspective of the target tissue to a clinician.Alternately, the fiber optic cable “FC” may be provided adjacent to thedistal radiating section 42 (see FIG. 5 for example). In thisembodiment, one or more lenses (not shown) may be provided adjacent tothe distal radiating section 42 and coupled to a distal end of the fiberoptic cable “FC.” Further, one or more force sensor “FS” configured toprovide feedback on force being applied by the distal radiating section42 to penetrate tissue. In this instance, the force sensor “FS” may beoperably coupled adjacent the distal radiating section (see FIG. 5 forexample).

In embodiments, one or more chemical sensor “CS” may be configured todetect one or ore chemicals of tissue prior to, during or afteractivation of the distal radiating section 42 (see FIG. 5 for example).In this embodiment, the chemical sensor “CS” may be in operablecommunication with the microcontroller 17 that is configured to detectchemicals associated with the target tissue, e.g., acids and proteins.The chemicals detected may be correlated to a progression of thermalablation growth and stored in one or more data look-up tables (notshown) that is accessible to the microcontroller 17.

FIG. 44 illustrates a method of placement configuration for varioussensor configurations. Specifically, alternate airways may be utilizedto deploy sensors (e.g., acoustic, thermocouples, electrical sensors,etc). In one particular embodiment, the ablation catheter 14 may beextended through the extended working channel 90 and positioned inbetween two opposing sensors, e.g., acoustic sensors “AS” that arepositioned in opposite airways. During operation of the distal radiatingsection 42, a ping across the airways can be generated to measure tissueproperties, e.g., measure impedance, dielectric or temperature.

FIG. 45 illustrates another feedback mechanism that may be utilized withthe system 10. In this embodiment, two antennas for ablation (e.g.,procedural/completeness) monitoring are provided, a sensor patch 1840and a distal radiating section 1842 of an ablation catheter 1814 (shownnot positioned within an extended working channel for clarity). Sensorpatch 1840 is positionable on a patient and configured to calibrate theablation catheter 1814 prior to treating tissue and determine when thetissue has been adequately ablated. The sensor patch 1840 is in operablecommunication with controller 17 configured to monitor the amount ofpower received by the sensor patch 1840 as the distal radiating section1842 is energized. The graph indicates received power at the sensorpatch 1840 during both calibration (points A-B) and an ablation cycle(points C-D). The calibration cycle baselines transmission path. Asablation progresses, transmission path between distal radiating section1842 and sensor patch 1840 becomes less lossy due to desiccationresulting in increasing received power. Ablation completeness isdetermined by amount of increased power received above calibration. Forexample, 1.5 cm ablation zone “AZ” increases power to sensor patch 1840by approximately 15%. In an embodiment, when the power at the sensorpatch 1840 reaches the calibration level or surpasses the calibrationlevel, the microcontroller 17 automatically shuts power off to ablationcatheter 1814.

While several embodiments of the disclosure have been shown in thedrawings, it is not intended that the disclosure be limited thereto, asit is intended that the disclosure be as broad in scope as the art willallow and that the specification be read likewise. Therefore, the abovedescription should not be construed as limiting, but merely asexemplifications of particular embodiments. Those skilled in the artwill envision other modifications within the scope and spirit of theclaims appended hereto.

1. (canceled)
 2. A microwave ablation system, comprising: a microwaveenergy source; a tool for treating tissue, the tool receiving microwaveenergy from the microwave energy source; and a guide catheter configuredto navigate a luminal network and position the tool adjacent a target,the guide catheter including a plurality of lumens.
 3. The microwaveablation system according to claim 2, wherein the plurality of lumenscomprises three lumens, the three lumens substantially forming in across-section of the guide catheter a circumference adjacent an innerside of an outer perimeter of the guide catheter.
 4. The microwaveablation system according to claim 3, wherein the plurality of lumenscomprises at least one further lumen, the at least one further lumensubstantially forming in the cross-section of the guide catheter afurther circumference adjacent an inner side of the three lumens.
 5. Themicrowave ablation system according to claim 2, wherein the plurality oflumens comprises four lumens, the four lumens substantially forming in across-section of the guide catheter a circumference adjacent an innerside of an outer perimeter of the guide catheter.
 6. The microwaveablation system according to claim 2, wherein the tool is a microwaveablation catheter comprising: a coaxial cable connected to a microwaveenergy source at the proximal end of the coaxial cable, and connected toa distal radiating section at the distal end of the coaxial cable, thecoaxial cable including inner and outer conductors and a dielectricpositioned therebetween, the inner conductor extending distally past theouter conductor and in sealed engagement with the distal radiatingsection; and a balun formed in part from a conductive materialelectrically connected to the outer conductor of the coaxial cable andextending along at least a portion of the coaxial cable, the conductivematerial having a braided configuration and covered by at least oneinsulative material, the balun being expandable.
 7. The microwaveablation system according to claim 6, wherein at least a portion of theouter conductor is removed to form a feedgap between the distalradiating section and the balun.
 8. The microwave ablation systemaccording to claim 3, wherein the guide catheter further comprises a hubat a proximal end thereof, the hub including at least one fluid intakeport and at least one fluid return port configured to provide respectiveingress and egress of a coolant to and from the plurality of lumens forcooling the ablation catheter.
 9. The microwave ablation systemaccording to claim 2, wherein a chamber is provided at a distal end ofthe guide catheter and is in fluid communication with at least thelumens dedicated for communication with the fluid intake port, thechamber surrounding the distal radiating section and configured toreceive a high boiling point liquid being therein to cool the distalradiating section.
 10. The microwave ablation system according to claim2, wherein a balloon is configured to be positioned adjacent the distalradiating section and is expandable to anchor the distal radiatingsection within the luminal network.
 11. The microwave ablation systemaccording to claim 10, wherein the balloon is thermally conductive andis configured to dissipate heat from the distal radiating section into awall of the luminal network when the distal radiating section isenergized.
 12. The microwave ablation system according to claim 2,further comprising at least one temperature sensor disposed proximatethe distal radiating section and configured to measure a temperature oftarget tissue while the distal radiating section is energized, the atleast one temperature sensor configured to communicate with atemperature sensor system that is in operable communication with amicrowave energy source.
 13. The microwave ablation system according toclaim 2, further comprising at least one position sensor coupled to atleast one of the catheter guide and the tool.
 14. A microwave ablationsystem configured for use in a luminal network, comprising: a microwaveenergy source; a tool for treating tissue, the tool receiving microwaveenergy from the microwave energy source; an extended working channelconfigured to provide passage for the tool, the extended working channelincluding a closed distal end and a multi-lumen configuration configuredto receive the tool; and a locatable guide positionable through theextended working channel and configured to navigate the extendableworking channel adjacent a target, the locatable guide including atleast three lumens, three of the at least three lumens substantiallyforming in a cross-section of the guide catheter a circumferenceadjacent an inner side of an outer perimeter of the guide catheter. 15.The microwave ablation system according to claim 14, wherein the atleast three lumens comprises at least four lumens, at least one of theat least four lumens substantially forming in the cross-section of theguide catheter a further circumference adjacent an inner side of thethree lumens.